Air circulating means for portable hammers



Aug. 1, 1933. .1. N. BAKER AIR CIRCULATING MEANS FOR PORTABLE HAMMERS Filed Aug. 14, 1951 3 Sheets-Sheet 1 Aug. 1, 1933. J. N. BAKER 1,920,673

AIR CIRCULATING MEANS FOR PORTABLE HAMMERS Filed Aug. 14, 1931 3 Sheets-Sheet 2 Aug. 1, 1933. J. N. BAKER AIR CIRCULA'IING MEANS FOR PORTABLE HAMMERS 3 Sheets-Sheet 3 Filed Aug. 14, 1931 Patented 1, 1 933 1 Application Au ustjiaies j s'e ieinb. 557,013

One of the important'difficulties encountered 1 inthe operation of the various portable hand" controlled power hammers which "it is necessary to provide for and overcome-in thedevelopment of a" tool of this type to make the tool conven y ient to use and satisfactory in -its'operation, is

V 'due to the generation of heat incident to the percussion or impact or' the ram} upon the bit or anvil and'to a lesser degree tothe reaction of this impact upon the mechanical parts of the hamme'rpand "tosome eiitentto the friction of thereciprocatingpart's; i V

The heat thus generated in'the operation of:

. the tools now in use iscommunicatedto the workmg parts of the hammer "increasing "the friction and the wear. it is also transmitted by co nducg tionto the barrel and other parts which come in contact with the handsfof the'operator, mak

ing=it difiicult and unplea'sant' to operate the p the .parts therein; Figure 6 beingcontinuous with tool; detracting to the work.

'The present invention relates to improvements whereby the heat-generated in the operation of the'tool is dissipated and theharmfu1'efleots*in adegree from the precision of cident to 'heatingfiare completely overcome re sulting in an increase in the lengthoi are of the y tooland increased comfort to the operator, and

increased facility in its use. p p I a m some instances, notably the drilling of holes in concrete, brick, stone or other gritty sub stances whichiorm a dust having an abrasive a'ctionQ'it is essential that the du'st from the opera-- tion be prevented from entering the' working chamber "of the toolwhereit would result indecreasing the -e'fiicienc'y and'infvery-rapid deterioration of 'the parts; The dust and chips also accumulate in the hole being drilled, and interfere" with the efiicient operation 'cilthe tool by increasing the friction and shielding or tending to "shield the material being cut. p

In the operation of the improved tool the' dust is excluded from the working'chamber and from the vicinity of the work, aiding the vision v of the operator, and the dust and cuttings "are 818- pelled from-this 'hole being drilled or cut in the 7 w k- I i r 'In the accompanying drawings I have' illuu-i trated a power hammer both of the type having a rotary motor and crank and also the'solenoiclt'yp'e'of hammer showing the application of In the" drawings v the invention to 'tools' of these 'various' types tion, the barrel being shown in section 'on-a with the illustration', Figure 3.

dust separator is of a well'knowntypea I plane of the'vertical" axis and the'lower half .being jibroken away for convenience of illustration. Figure '2 is an axial-section showing the lower end of theahamrner barrel and the parts" con tainedxtherein; the same being continuous with' Figure 1. :1. It Figure "3 isaivertical section taken on-a plane of theiaxis showing. a hammerlof the solenoid type equipped inlaccordance withptheinvention; I

Figure 41s an externalelevation' onflareducedfi d a scale of a hammer constructed in accordance Figure;5 is a section on aflplane iofft hehami- 1116i axis illustratingftheapplication of the'in-g I vention to a hammerof a construction embodying;-

'the featuresof both types of Figure 1 and Figure 3, s

the lower end of the barrel being broken awayp I 1 Figure ,6 is a section in the same plane as Figure 5, showing thelowerlend off the" barrel and Figure 5.-

Referring to the drawingspby I first having freference to. the i hammershqwnj in Figures ;1 and '2, the construction includesfln; electric motor. 1, enclosed in a) motor housing or casing 2; .Thiscas'ing as shown contains inaddition to the motor a centrifugal fand'mdurit 1 ed on. the motor shaft 10 at the lefty-ins Figure-1 1. Thisgfan. draws the'airf in at openings} in:

; thecasing at' the oppositeendfromthefan leading it through passages v5 through and around the' field and" armature windings andiprojecting it downwardly througha passage or passages-6 I into the crank case 7. The construction s as shown 'also'in'cludes Iafcentrifugal rotary dust" separator 8 mounted onthe motor sha'itiat the right immediately adjacent the openings 4': This crank case 7; The crank case 7 contains a"crank disk- 11 secured'to a shaft 12 having suitable b'earings at M inthe frameor casing. Thecrank disl 11 "is driven from themotor'by'thereducing gear train 16, 1'7 and 18. l i

The crank "disk '1 1 carries acrank pin l 9 which operates a dependingjcon'necting rod 20, which 5 in turn operates the ram 21"being-connect'ed;

thereto by means ojfiwris't pin 22 niountedin ears 24 projecting" upwardly from the ram; The" ram is shown as infthe form of an "elongated piston" arranged-tent and slide in a "guide-sleeve 25 I and 'to cooperate therewith after-the manner of closed within and spaced inwardly from the ham mer barrel26; which extends downwardly from the crankcase 7,being secured thereto by flanges 27, and the spacing of the sleeve 25 from the barrel 26 forms an annular air space or'jacket. 23 which in the preferred'iorm extends prac I tically from one end of'the sleeve to the other and around thesleeve forming a jacketwhich isas nearly complete as is found convenient. The space 21 within the sleeve 25 at the top is 'connected to the crank case? by a port or open:

ing 28.

The. guide sleeve .25 is provided atits upper ing actuated by the solenoidcoils 93"as' they are end with ports31 above the .top of the ram'2l in its uppermost position .andwith ports 32 near itslower end and spaced upwardly therefrom to be'covered by the ram as it 'approaches'the lower end of its stroke whereit contacts theshank of the tool or bit 33 in the tool bushing '30 providedi'for this purpose in'. the lowerend-of the barrel;v The air in the pathof the'rain vas it descends is directed into contact with th5;WOlk

through openings l'l at thesidesof the bushing, and-jopening 46 leading downwardly through the tool along its axis; I I

Figures'3 and 4 show a hammer of the solenoid :type 7 having an. external cylindrical case,

ing orw barrel .40 in which solenoids 41 and-'42 are mounted one above the other concentric with thebarrel. These solenoids are shown as spaced inwardly from the barrel forming a peripheral airchamber or jacket 43. The barrel shown in this figure is provided at its lower end with a removableplugorclosure 44"forrning the lower end,of the barrel and this plug .or. closure 44' is equipped, with ai-tool and bit bushing-45 con V taining a bit 33 having an axial opening or air Figure 2. I

The passages. 46 and l'l are, in this instance v suppliediwith airffromacentral guide sleeve 48 which extends substantially from. one end of the barrel totheother coaxiallyl therewith, being sup- I portedat :its'u'pper end in a circular seat 50- having ia cylindrical protuberance 50" whiclrfits tightly within the end of the sleeve, and at its -50 lower end as shown it bears against the plug 44, being seated. between the ends of the ribs 44 v thereon; This-plug or end 44 is centrally aperturedat 51 surrounding the upperend of the shank of theftool orbit 111, which is seated in the tool1bushing 45, the shank of this bit projecting upwardly therefrom.

-The sleeve or guidevsleeve 48 servesasia guide for thereciprocating ram' 53 whichv is the core ofsolenoids '42 and'43. This ram as shown is. cylin- 'dricalin form andadapted to fitfand slide in the a sleeve or bushing 48 afterathe manner of a piston in its cylinder.

57, and the air is admitted through the seat by way of-the. port58 which leads'to the'upper end of. the sleeve 48 and there is aball valve 59cmgaging the seat. 5.7,and supported on the seatby means of a coil spring GO. The guide sleeve 48,

has'in addition to the port 58 a port (ll-near its 'upper end and port 62 near its lower end. Figure 4 shows this hammer equipped with a handle 63. fInv-Figuresfiand 61 have shown a hammer of passage. 46 identicalwith that'shown .in Figure 2, and there. are'also downwardly-disposed air passages 47 at the sides of the bushing'4d; as in the solenoid typeembodying features'of both of l the constructions previously described. ,This

construction includes anouter casing 90, having a handle 91 at its upper end, and containing a chamber 92 in which is a double solenoid 93 surrounding a central guide sleeve 9.4fmounted at .the center of "the chamber 92 within the casing in line with the axisof the same, beings'ecured in the casing at itslu'pper and lower ends. -The casing is provided at its upperend at the. center oithe guide sleeve 94,'-with an air inlet passage controlled by valve 95'w'hich opens inwardly-,i. e., "into the guide sleeve. A'solenoid core 96 operates in the guide sleeve as a piston in its cylinderbeenergized alternately in accordance with the regular practice intheoperation of such a solenoid.

""The 'core 96'is cushioned and checked at the --opposite ends of its stroke by helical springs 9'7 and 98 mounted in the opposite ends of the guide sleeve and bearing against the endsof. the casing within the guide'sleeve; the upper'and lower ends or" the casing'withinthe guide serving as abutwardly from the end .of the sleeve, and leading by the arrows.

' Secured to the lower end of thesol'enoid casing e 90 in alignment therewith is. the-hammerbarrel" ll. Within this barrel and preferably concentric therewith is a ram guide sleeve ,72 containinga ram 73 whichfits and slides in the sleeve after the solenoid guide sleeve 94 downwardly into the ram guide sleeve '72 allowing a considerable air passage around the rodirom one guide sleeve to the other as indicated by the arrows; The spring 9'7 as shown encircles therod 74 bearing onthe por- I tion of the end wall'76 of theca'sin'g 90whereit formsa shoulder 77 surrounding the opening75; it being'noted that the end wall 76 is countersunk to admit the uide sleeve '94. The ram guide sleeve 7251s provided with airports "78 at itsnpper end leading outwardly from within the sleeve from said chamber 92 into the sleeveas indicated into an annular space '791which forms a pocketor a air jacket between the barrel andtheguide sleeve,

and the sleeve is provided -:near .its lower. end

spaced upwardly from the end wall 30 or plug at the lower end of-the barrel with'air-ports 81;

' The lower end of the barrelor plug80 is pro vided with a tool bushing82 enclosing a bit 83,,

and it is shown as provided with air discharge openings84 discharging in the general direction of the work. The tool orbit 83 .:is shown as having a central axially placed air passage 85 with. discharge openings 86 near the lowerend and disposed downwardly in' the general direction of cutting.

Referring 'now. to the operation of; the typegof hammer shown in Figure .1, when the ramg21.;

is in. uppermost position, the ports 32 at the lower end of the guide sleeve 25 are uncovered and the air in the annular space '23-being under 1 pressure somewhat in excess of atmosphere as hereinafter described, fiowsfreely into the space beneath the lower end of the ram indicated by reference character 23' in Figure 2. Asthe ram 21 descends, these ports 32 are covered by the ram and closed, and the air contained in the I chamber 23' is compressed and discharged either through the ports'47 in the'lower end of the barrel, or throughthe opening 46 in the bit or tool 33. In either case the air so exhausted serves to clear the surface of the work near the cutting edge of the tool of accumulated dust and chips.

. The ejection of the air through the tool operates toparticular advantage to clear the surface of the work-or the hole being cut of debris which might interfere with the cutting operation. The air from the fan 3 forced downwardly into crank case 7 is admitted to the space 21 over the ram as the ram advances on the down stroke and is expelled through ports 3l into jacket 23 on the upstroke. A slight pressure maintained in crank case 7 by the fan prevents the return of the air through port 28. From port 31 the air passes downwardly through jacket 23 nearly to the lower end of the barrel where it passes through ports 32 into working chamber 23 in the guide sleeve below the ram. From this space it is ejected as described maintaining a continuous'circulation through jacket 23. The slight pressure in the port 28 assists in this circulation to the extent that it prevents a back draft through ports 46 and 47 with consequent entrance of grit into working chamber 23 which would cause rapid and very harmful wear of the guide sleeve and ram. The air circulation described has a'very important effect in carrying away the heat caused by the friction of theram 21upon the walls of the sleeve 25 as well as that produced by the im-;

pact upon the tool, thus .tendin'gtdretain the temperature of the barrel which is grasped by the operator in guidingthe tool and. also the temperature of thecasing with which the hands of V the operator must come in frequent contact withpassed through the annular jacket 23 between the barrel 26 and the guide sleeve 25 containing the ram 21; being later expelled from chamber 23 by the down stroke of the ram, is particularly effective.

Referring now to i the construction disclosed in Figures 3 and 4, it is evident that the ram and solenoid core 53 upon its downward stroke draws I air through the check valve 59 into the guide sleeve 48 above the core, the space being indicated by reference character 100; This air is forced by the ram or core upon its return or up stroke through the port 61 into the portion of the cham,- ber 43 surrounding the guide sleeve 48 and con--. taining the solenoid coils 41 and 42, and thence through this chamber and around the coils down wardly to the ports 62, and as the ram uncovers f theport 62 on its upward stroke, the air from.

chamber 43 rushes through the port 62 into the space 101 belowthe ram 53, whence it is forcibly theports 62 are covered. From space 101 the air is discharged either through the ports 47 or the Q axial passage 46 through the tool 33 in either of head' of the tool 33.

which instances it serves to remove the 'dust from the point of cutting and fronithe vicinity of the work.

The circulation of air as described is very efiecg tive' in carrying away the heat'caused by electrical losses in the operating coils 41. and 42, also the heatproduced by the friction of the ram 53 upon the walls of the sleeve 48 aswell as that produced by the impact of the ram upon the In this way the operating temperature of the parts within the barrel, i. e.,

the lower unit, is reduced protecting the hands of the operator and preventing'the collection of dust within the chamber 101- where it would cause a considerable amount of damage on'account of its abrasive action. i

In the operation of the tool shownin Figures 5 andG, the operation of the solenoid 96 which is the same so far as the pumping action is concerned as that of the solenoidcore or ram 53,

forces the airthus compressed downwardly through the opening into the chamber 92" at the upper end'of-the ram guide sleeve '72 above the ram. 011 the upstroke of the ram 73 the air contained in this chamber:v is forced outwardly thedown stroke of the ram, the ports 61 being closed by the ram, the air contained in the chamber 93' at the lower end of the sleeve 79 is, compressed and ejected through the ports or passages 34 or through the passage extending longitudinally through the tool 83. In either inthe workand servesto clear the vicinity of -the work and the cutting edge and the immediate dust and chips. The effect of .the pumping action of the solenoidcore 96 is of particular importance in that it maintains the pressure and prevents entrance of grit into the chamber 93},

pumping action of the ram' '73 effecting and maintaining a satisfactory cooling of the reciprocating parts, including the ram, the guide sleeve 72 with which it contacts; and particularly" it serves to cool the barrel 71 which is grasped by the-operator, making the operation ofJthetool 'stancethe air is discharged in the direction of vicinity thereof preventing the accumulation of c "-3 and it greatly increases the efficiency of the comfortable to. the operator and-therefore increasing its efficiency] 7 I In every instance thecooling action is important not only in that itcontributes to the comfort: of the operator and therefore the efficiency with which the work is done,but by preventing heating of the reciprocating'parts, it decreases wear and increases the life of the tool. The im-' portance of excluding theggrit from the ram guide has been fully explained as has also the desirability of clearing away thefidust and chips from'the vicinity of the cuttingoperation and particularly from the point of cutting. w'Ihese results are accomplished most effectively;

I have thus describedspeciflcally and in de- I tail a' power'hammer in which the ram operates as a pump to provide a cooling circulation and to expel dust and grit from the vicinity of the the manner of constructing, operating, applying and using theinvention maybe fully understood,-

1. In a portable power hammer'a reciprocating v 4 ram, a barrel enclosing the ram and guiding means therefor with an air cooling passagefe xf tending. longitudinally of the barrel, the ram fit work including in the preferred form 'Of t1l6 in v vention meansfor forcing the air into-the path of the rain to facilitate this operation. The description is specific and in detail in order thatting in the guide after the manner of av piston in its cylinder, means for introducingair into the guide in the path of the ram atone end, a discharge port, at the other end and ports connecting the pass'ageto the opposite ends of the guide whereby the ram as it reciprocates forces air into the passage at one end, the guide receiving air from the passage at'the other end, the

the guide as the ram advanoea'which air the o port connecting the air cooling'passage to the? guide adjacent the striking end of the ram being in the path of the remand spaced-backwardly from the end of said path so that after admitting air to the guide the ram, as it advances, covers the port, whereby the ram in its operation forcibly expels the airthus trapped in the guide through said discl'iarge port. A

2. In a portable power hammer a reciprocating ram, a barrel enclosing the ram and having guide ing means therefor with an air cooling passage, the ram fitting in the guide after the manner of a piston-in its cylinder and operating therein withla pumping action at both ends, means for admitting air to the guide and into the path of the ram at one end, a discharge port leading from the path of the at the other, end of the guide, and, ports connecting the opposite ends of the guide to the oppositeends of the air passage whereby the ram as it reciprocates forces airinto the passage at one endthe port connecting the air passage to the end of the guide toward the'work being in the path of the rainand spaced backwardly from the end of the path'whereby it is covered as the ram advanceswhereby the air enters the guide from the passage on the backstroke ,of' the ram, the'air being compressed in ram in its operation expels through said discharge port, said discharge port being'directed ,into the vicinity of the work, the draft of air means for passing air through said port,' the ram operating toexpel air fromthe guide into said passage which hasan admission port adiacent said first mentioned port for this purpose,

the passage also havingfa port at its opposite end leading into the opposite end of the guide, id

port being covered by, the ram as it descends: the ram serving to compress the air irornthe passage when said port is covered, and to expel this air,

'the construction including a discharge opening for this purpose.

4. In a portable power hammer a ram and a 1 barrel therefor including guiding'means for the ram and an air passage extending longitudinally thereof to cool the barrel and ram, the ram fitting in the barrel and being arranged to'operate in connection with the opposite ends of the barrel after the manner of a double acting pump, said barrel having means for admitting the air at one end into. the path of theram for releasing it therefrom into said passage as the ram advances and means for discharging it from the oppo to end of the passage into the path of the ram,-'said discharging means consisting of a port in the path of the ram spaced back from the striking end of theramstroke to be covered by the ram as it advancescompressing the air in the guide the ram serving to expel the air thus withdrawn from the passage, and a motor connected to the ram to operate the ram, said motor having air circulating means whereby the compressed air supplyis means for reciprocating the ram, a ram guide in which the ram operates as a piston, and a barrel surrounding the guide and spaced outwardly therefrom providing an air passage for cooling the surface of the barrel and the ram, means for delivering air to the upperend of the guide above the ram, and a port through which-it is expelled by the ram into the upper end of the air passage, an admission port connectingthe lower endof the air passage to the lower portion of the-guide and adapted to be covered by the rain as it descends, and a discharge port for discharging the airirombeneath the ram which as it descends, closes the admission port and compresses and expelsthe airv in its pathffand on its upstroke unply fromsaid passage. 7 I p 6. In a portable powerhammer a ram, power means for reciprocating the ram, a ram guide and a barrel surrounding the ram guide and spaced outwardly therefrom providing an-air passage for cooling the surface of thebarrel and the ram and guide, ineansifor compressing'air to a pressure slightly in excess of'atmos'phere anda portfor coversthe admission port admitting a new supadmittingthe compressed air to the upper end of 1 said air passage, an admission port near the lower end oi the barrel to deliver air fromsaid passage into the path of the ram, and'an opening for dis char. ing air from beneath the ram which, com

presses and; expels the air thus ,delivered on its down stroke. and on its upstroke idraws in a new supply i roinsaid passage into the-space beneath the rain. r 7. In a portable power hammer, a ram, means of atmosphere to the upper end of the-jacket,

means for supporting a bit in the path of the ramat the lower end of the guide, a port for leading air from the jacketinto the guide between for reciprocating the ram, aguide in which the the ram and the bit, a passage for delivering the I air therefrom inthegdirection of the work, the port being covered by the ram as it moves downwardly toward the biti expelling the air through said passage in the direction of the work, the ram g on the upstroke serving to draw the'air from the 13- jacket into the guide beneath the ram, thu maintaining a continuous circulation'.'l 9

7 8. In a portable power hammer, a ram, a guide :for ram in. which the ram operates asa piston in'its cylinder, means for reciprocating the ram,

, a barrel surrounding the guide and having at its pressure in excess of atmosphere into the path of the on its upward stroke and a port where by the is caused to force the air into the barrel, a passage. for conducting this air along the'barrel in contact with the guide andbarrel to the lower end of thebarrel, means for deliver-.

ing the air thus passed along the barrel into the path of-the ram in the vicinity'of the bit, the

rain'on itsdownward stroke serving to eject the air from the barrel and on its upward stroke from said passage.

drawing in a new supply 7 a f JAMES -N. BAKER. 

